Day23（53）-F:\硕士阶段\Java\课程代码\后端\web-ai-code\web-ai-project02\aliyun-oss-spring-boot-autoconfigure

SpringBoot原理

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打包jar包，通过maven

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打开当前文件夹，cmd

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java -jar springboot-web-config-0.0.1-SNAPSHOT.jarjava -jar springboot-web-config-0.0.1-SNAPSHOT.jar

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java -Dserver.port=9000 -jar springboot-web-config-0.0.1-SNAPSHOT.jar

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java -Dserver.port=9000 -jar springboot-web-config-0.0.1-SNAPSHOT.jar --server.port=10010

命令行参数优先级最高，高于系统属性

image-20251202135529528

外部配置文件（命令行参数和系统属性）优先级高于内部（yml这些），可以用来修改代码

F:\目标目录>java -jar springboot-web-config-0.0.1-SNAPSHOT.jar --server.port=10010 --spring.datasource.username=testUser --spring.datasource.password=testPwd666

Bean管理

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/**
 * 默认IOC容器中的bean是单例的，也就意味着singleton；在项目启动时创建一次，后将该bean存入IOC容器中
 */
//@Lazy//延迟初始化至第一次使用的时候，再来创建这个bean
@Scope("prototype")//prototype原型，非单例多例
@RestController
public class DeptController {

    public DeptController() {
        System.out.println("创建DeptController对象");
    }

    @Autowired
    private DeptService deptService;

    /**
     * 查询全部部门
     */
    @GetMapping("/depts")
    public Result findAll(){
        List<Dept> deptList = deptService.findAll();
        return Result.success(deptList);
    }

    /**
     * 根据ID删除部门
     */
    @DeleteMapping("/depts")
    public Result delete(Integer id){
        System.out.println("根据ID删除部门数据: " + id);
        deptService.delete(id);
        return Result.success();
    }

    /**
     * 新增部门
     */
    @PostMapping("/depts")
    public Result save(@RequestBody Dept dept){
        System.out.println("新增部门数据: " + dept);
        deptService.save(dept);
        return Result.success();
    }

    /**
     * 根据ID查询部门信息
     */
    @GetMapping("/depts/{id}")
    public Result getInfo(@PathVariable Integer id){
        System.out.println("根据ID查询部门数据: " + id);
        Dept dept = deptService.getInfo(id);
        return Result.success(dept);
    }

    /**
     * 修改部门
     */
    @PutMapping("/depts")
    public Result update(@RequestBody Dept dept){
        System.out.println("修改部门数据: " + dept);
        deptService.update(dept);
        return Result.success();
    }
}

image-20251202143805610

image-20251202150845360

package com.itheima.utils;

import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.CredentialsProviderFactory;
import com.aliyun.oss.common.auth.EnvironmentVariableCredentialsProvider;
import com.aliyun.oss.common.comm.SignVersion;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import java.io.ByteArrayInputStream;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.UUID;

//@Component
public class AliyunOSSOperator {
    //@Autowired
    private final AliyunOSSProperties aliyunOSSProperties;

    public AliyunOSSOperator(AliyunOSSProperties aliyunOSSProperties) {
        this.aliyunOSSProperties = aliyunOSSProperties;
    }

    public String upload(byte[] content, String originalFilename) throws Exception {
        String endpoint = aliyunOSSProperties.getEndpoint();
        String bucketName = aliyunOSSProperties.getBucketName();
        String region = aliyunOSSProperties.getRegion();

        // 从环境变量中获取访问凭证。运行本代码示例之前，请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();

        // 填写Object完整路径，例如2024/06/1.png。Object完整路径中不能包含Bucket名称。
        //获取当前系统日期的字符串,格式为 yyyy/MM
        String dir = LocalDate.now().format(DateTimeFormatter.ofPattern("yyyy/MM"));
        //生成一个新的不重复的文件名
        String newFileName = UUID.randomUUID() + originalFilename.substring(originalFilename.lastIndexOf("."));
        String objectName = dir + "/" + newFileName;

        // 创建OSSClient实例。
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
        OSS ossClient = OSSClientBuilder.create()
                .endpoint(endpoint)
                .credentialsProvider(credentialsProvider)
                .clientConfiguration(clientBuilderConfiguration)
                .region(region)
                .build();

        try {
            ossClient.putObject(bucketName, objectName, new ByteArrayInputStream(content));
        } finally {
            ossClient.shutdown();
        }

        return endpoint.split("//")[0] + "//" + bucketName + "." + endpoint.split("//")[1] + "/" + objectName;
    }

}

（不推荐）

package com.itheima;

import com.itheima.utils.AliyunOSSOperator;
import com.itheima.utils.AliyunOSSProperties;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;


@SpringBootApplication
public class SpringbootWebConfigApplication {

    @Bean
    public AliyunOSSOperator abc(@Autowired AliyunOSSProperties aliyunOSSProperties){
        return new AliyunOSSOperator(aliyunOSSProperties);
    }
    public static void main(String[] args) {
        SpringApplication.run(SpringbootWebConfigApplication.class, args);
    }

}

package com.itheima.config;

import com.itheima.utils.AliyunOSSOperator;
import com.itheima.utils.AliyunOSSProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class CommonConfig {
    @Bean
    public AliyunOSSOperator abc(AliyunOSSProperties aliyunOSSProperties){
        return new AliyunOSSOperator(aliyunOSSProperties);
    }
}

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起步依赖

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自动配置

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package com.itheima;

import com.itheima.utils.AliyunOSSOperator;
import com.itheima.utils.AliyunOSSProperties;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
//自动配置的实现方案一@ComponentScan+@Component
@ComponentScan(basePackages = {"com.example","com.itheima"})
@SpringBootApplication//具备组件扫描功能，但是默认扫描的是启动类所在包及其子包，扫不到其他工具包的
public class SpringbootWebConfigApplication {

//    @Bean
//    public AliyunOSSOperator abc(@Autowired AliyunOSSProperties aliyunOSSProperties){
//        return new AliyunOSSOperator(aliyunOSSProperties);
//    }
    public static void main(String[] args) {
        SpringApplication.run(SpringbootWebConfigApplication.class, args);
    }

}

package com.example;

import org.springframework.stereotype.Component;

@Component
public class TokenParser {

    public void parse(){
        System.out.println("TokenParser ... parse ...");
    }

}

package com.example;

import org.springframework.context.annotation.ImportSelector;
import org.springframework.core.type.AnnotationMetadata;

public class MyImportSelector implements ImportSelector {
    public String[] selectImports(AnnotationMetadata importingClassMetadata) {
        return new String[]{"com.example.HeaderConfig","com.example.TokenParser"};
    }
}

package com.example;

import org.springframework.context.annotation.Import;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
@Import(MyImportSelector.class)
public @interface EnableHeaderConfig {
}


package com.itheima;

import com.example.EnableHeaderConfig;
import com.example.HeaderConfig;
import com.example.MyImportSelector;
import com.example.TokenParser;
import com.itheima.utils.AliyunOSSOperator;
import com.itheima.utils.AliyunOSSProperties;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Import;
//自动配置的实现方案一@ComponentScan+@Component
//@ComponentScan(basePackages = {"com.example","com.itheima"})

//自动配置的实现方案二：@Import
//@Import(TokenParser.class)//普通类
//@Import(HeaderConfig.class)

//自动配置的实现方案三：基于@Import导入ImportSelector接口的实现类
//@Import(MyImportSelector.class)//是ImportSelector接口的实现类-批量导入

//自动配置的实现方案四：基于注解
@EnableHeaderConfig
@SpringBootApplication//具备组件扫描功能，但是默认扫描的是启动类所在包及其子包，扫不到其他工具包的
public class SpringbootWebConfigApplication {

//    @Bean
//    public AliyunOSSOperator abc(@Autowired AliyunOSSProperties aliyunOSSProperties){
//        return new AliyunOSSOperator(aliyunOSSProperties);
//    }
    public static void main(String[] args) {
        SpringApplication.run(SpringbootWebConfigApplication.class, args);
    }

}

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源码

  1. 启动类也是配置类，@SpringBootApplication封装了@SpringBootConfiguration封装了@Configuration

  2. 启动类能扫描的原因是@SpringBootApplication封装了@ComponentScan

  3. @SpringBootApplication封装了@EnableAutoConfiguration封装了@Import({AutoConfigurationImportSelector.class})，AutoConfigurationImportSelector继承了 DeferredImportSelector继承了ImportSelector。下面是AutoConfigurationImportSelector的代码

    public String[] selectImports(AnnotationMetadata annotationMetadata) {
    if (!this.isEnabled(annotationMetadata)) {
        return NO_IMPORTS;
    } else {
        AutoConfigurationEntry autoConfigurationEntry = this.getAutoConfigurationEntry(annotationMetadata);
        return StringUtils.toStringArray(autoConfigurationEntry.getConfigurations());
    }
}

protected List<String> getCandidateConfigurations(AnnotationMetadata metadata, AnnotationAttributes attributes) {
    ImportCandidates importCandidates = ImportCandidates.load(this.autoConfigurationAnnotation, this.getBeanClassLoader());
    List<String> configurations = importCandidates.getCandidates();
    Assert.state(!CollectionUtils.isEmpty(configurations), "No auto configuration classes found in META-INF/spring/" + this.autoConfigurationAnnotation.getName() + ".imports. If you are using a custom packaging, make sure that file is correct.");
    return configurations;
}

META-INF/spring/" + this.autoConfigurationAnnotation.getName() + ".imports.

image-20251202172928743

org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration
org.springframework.boot.autoconfigure.amqp.RabbitAutoConfiguration
org.springframework.boot.autoconfigure.aop.AopAutoConfiguration
org.springframework.boot.autoconfigure.availability.ApplicationAvailabilityAutoConfiguration
org.springframework.boot.autoconfigure.batch.BatchAutoConfiguration
org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration
org.springframework.boot.autoconfigure.cassandra.CassandraAutoConfiguration
org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration
org.springframework.boot.autoconfigure.context.LifecycleAutoConfiguration
org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration
org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration
org.springframework.boot.autoconfigure.couchbase.CouchbaseAutoConfiguration
org.springframework.boot.autoconfigure.dao.PersistenceExceptionTranslationAutoConfiguration
org.springframework.boot.autoconfigure.data.cassandra.CassandraDataAutoConfiguration
org.springframework.boot.autoconfigure.data.cassandra.CassandraReactiveDataAutoConfiguration
org.springframework.boot.autoconfigure.data.cassandra.CassandraReactiveRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.data.cassandra.CassandraRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseDataAutoConfiguration
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseReactiveDataAutoConfiguration
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseReactiveRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchDataAutoConfiguration
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.data.elasticsearch.ReactiveElasticsearchRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.data.jdbc.JdbcRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.data.jpa.JpaRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.data.ldap.LdapRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration
org.springframework.boot.autoconfigure.data.mongo.MongoReactiveDataAutoConfiguration
org.springframework.boot.autoconfigure.data.mongo.MongoReactiveRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.data.mongo.MongoRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.data.neo4j.Neo4jDataAutoConfiguration
org.springframework.boot.autoconfigure.data.neo4j.Neo4jReactiveDataAutoConfiguration
org.springframework.boot.autoconfigure.data.neo4j.Neo4jReactiveRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.data.neo4j.Neo4jRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.data.r2dbc.R2dbcDataAutoConfiguration
org.springframework.boot.autoconfigure.data.r2dbc.R2dbcRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration
org.springframework.boot.autoconfigure.data.redis.RedisReactiveAutoConfiguration
org.springframework.boot.autoconfigure.data.redis.RedisRepositoriesAutoConfiguration
org.springframework.boot.autoconfigure.data.rest.RepositoryRestMvcAutoConfiguration
org.springframework.boot.autoconfigure.data.web.SpringDataWebAutoConfiguration
org.springframework.boot.autoconfigure.elasticsearch.ElasticsearchClientAutoConfiguration
org.springframework.boot.autoconfigure.elasticsearch.ElasticsearchRestClientAutoConfiguration
org.springframework.boot.autoconfigure.elasticsearch.ReactiveElasticsearchClientAutoConfiguration
org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration
org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration
org.springframework.boot.autoconfigure.graphql.GraphQlAutoConfiguration
org.springframework.boot.autoconfigure.graphql.data.GraphQlQueryByExampleAutoConfiguration
org.springframework.boot.autoconfigure.graphql.data.GraphQlQuerydslAutoConfiguration
org.springframework.boot.autoconfigure.graphql.data.GraphQlReactiveQueryByExampleAutoConfiguration
org.springframework.boot.autoconfigure.graphql.data.GraphQlReactiveQuerydslAutoConfiguration
org.springframework.boot.autoconfigure.graphql.reactive.GraphQlWebFluxAutoConfiguration
org.springframework.boot.autoconfigure.graphql.rsocket.GraphQlRSocketAutoConfiguration
org.springframework.boot.autoconfigure.graphql.rsocket.RSocketGraphQlClientAutoConfiguration
org.springframework.boot.autoconfigure.graphql.security.GraphQlWebFluxSecurityAutoConfiguration
org.springframework.boot.autoconfigure.graphql.security.GraphQlWebMvcSecurityAutoConfiguration
org.springframework.boot.autoconfigure.graphql.servlet.GraphQlWebMvcAutoConfiguration
org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAutoConfiguration
org.springframework.boot.autoconfigure.gson.GsonAutoConfiguration
org.springframework.boot.autoconfigure.h2.H2ConsoleAutoConfiguration
org.springframework.boot.autoconfigure.hateoas.HypermediaAutoConfiguration
org.springframework.boot.autoconfigure.hazelcast.HazelcastAutoConfiguration
org.springframework.boot.autoconfigure.hazelcast.HazelcastJpaDependencyAutoConfiguration
org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration
org.springframework.boot.autoconfigure.http.client.HttpClientAutoConfiguration
org.springframework.boot.autoconfigure.http.client.reactive.ClientHttpConnectorAutoConfiguration
org.springframework.boot.autoconfigure.http.codec.CodecsAutoConfiguration
org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration
org.springframework.boot.autoconfigure.integration.IntegrationAutoConfiguration
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration
org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration
org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration
org.springframework.boot.autoconfigure.jdbc.JdbcClientAutoConfiguration
org.springframework.boot.autoconfigure.jdbc.JdbcTemplateAutoConfiguration
org.springframework.boot.autoconfigure.jdbc.JndiDataSourceAutoConfiguration
org.springframework.boot.autoconfigure.jdbc.XADataSourceAutoConfiguration
org.springframework.boot.autoconfigure.jersey.JerseyAutoConfiguration
org.springframework.boot.autoconfigure.jms.JmsAutoConfiguration
org.springframework.boot.autoconfigure.jms.JndiConnectionFactoryAutoConfiguration
org.springframework.boot.autoconfigure.jms.activemq.ActiveMQAutoConfiguration
org.springframework.boot.autoconfigure.jms.artemis.ArtemisAutoConfiguration
org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration
org.springframework.boot.autoconfigure.jooq.JooqAutoConfiguration
org.springframework.boot.autoconfigure.jsonb.JsonbAutoConfiguration
org.springframework.boot.autoconfigure.kafka.KafkaAutoConfiguration
org.springframework.boot.autoconfigure.ldap.LdapAutoConfiguration
org.springframework.boot.autoconfigure.ldap.embedded.EmbeddedLdapAutoConfiguration
org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration
org.springframework.boot.autoconfigure.mail.MailSenderAutoConfiguration
org.springframework.boot.autoconfigure.mail.MailSenderValidatorAutoConfiguration
org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration
org.springframework.boot.autoconfigure.mongo.MongoReactiveAutoConfiguration
org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration
org.springframework.boot.autoconfigure.neo4j.Neo4jAutoConfiguration
org.springframework.boot.autoconfigure.netty.NettyAutoConfiguration
org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration
org.springframework.boot.autoconfigure.pulsar.PulsarAutoConfiguration
org.springframework.boot.autoconfigure.pulsar.PulsarReactiveAutoConfiguration
org.springframework.boot.autoconfigure.quartz.QuartzAutoConfiguration
org.springframework.boot.autoconfigure.r2dbc.R2dbcAutoConfiguration
org.springframework.boot.autoconfigure.r2dbc.R2dbcProxyAutoConfiguration
org.springframework.boot.autoconfigure.r2dbc.R2dbcTransactionManagerAutoConfiguration
org.springframework.boot.autoconfigure.reactor.ReactorAutoConfiguration
org.springframework.boot.autoconfigure.rsocket.RSocketMessagingAutoConfiguration
org.springframework.boot.autoconfigure.rsocket.RSocketRequesterAutoConfiguration
org.springframework.boot.autoconfigure.rsocket.RSocketServerAutoConfiguration
org.springframework.boot.autoconfigure.rsocket.RSocketStrategiesAutoConfiguration
org.springframework.boot.autoconfigure.security.oauth2.client.OAuth2ClientAutoConfiguration
org.springframework.boot.autoconfigure.security.oauth2.client.reactive.ReactiveOAuth2ClientAutoConfiguration
org.springframework.boot.autoconfigure.security.oauth2.client.reactive.ReactiveOAuth2ClientWebSecurityAutoConfiguration
org.springframework.boot.autoconfigure.security.oauth2.client.servlet.OAuth2ClientWebSecurityAutoConfiguration
org.springframework.boot.autoconfigure.security.oauth2.resource.reactive.ReactiveOAuth2ResourceServerAutoConfiguration
org.springframework.boot.autoconfigure.security.oauth2.resource.servlet.OAuth2ResourceServerAutoConfiguration
org.springframework.boot.autoconfigure.security.oauth2.server.servlet.OAuth2AuthorizationServerAutoConfiguration
org.springframework.boot.autoconfigure.security.oauth2.server.servlet.OAuth2AuthorizationServerJwtAutoConfiguration
org.springframework.boot.autoconfigure.security.reactive.ReactiveSecurityAutoConfiguration
org.springframework.boot.autoconfigure.security.reactive.ReactiveUserDetailsServiceAutoConfiguration
org.springframework.boot.autoconfigure.security.rsocket.RSocketSecurityAutoConfiguration
org.springframework.boot.autoconfigure.security.saml2.Saml2RelyingPartyAutoConfiguration
org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration
org.springframework.boot.autoconfigure.security.servlet.SecurityFilterAutoConfiguration
org.springframework.boot.autoconfigure.security.servlet.UserDetailsServiceAutoConfiguration
org.springframework.boot.autoconfigure.sendgrid.SendGridAutoConfiguration
org.springframework.boot.autoconfigure.session.SessionAutoConfiguration
org.springframework.boot.autoconfigure.sql.init.SqlInitializationAutoConfiguration
org.springframework.boot.autoconfigure.ssl.SslAutoConfiguration
org.springframework.boot.autoconfigure.task.TaskExecutionAutoConfiguration
org.springframework.boot.autoconfigure.task.TaskSchedulingAutoConfiguration
org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration
org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration
org.springframework.boot.autoconfigure.transaction.TransactionManagerCustomizationAutoConfiguration
org.springframework.boot.autoconfigure.transaction.jta.JtaAutoConfiguration
org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration
org.springframework.boot.autoconfigure.web.client.RestClientAutoConfiguration
org.springframework.boot.autoconfigure.web.client.RestTemplateAutoConfiguration
org.springframework.boot.autoconfigure.web.embedded.EmbeddedWebServerFactoryCustomizerAutoConfiguration
org.springframework.boot.autoconfigure.web.reactive.HttpHandlerAutoConfiguration
org.springframework.boot.autoconfigure.web.reactive.ReactiveMultipartAutoConfiguration
org.springframework.boot.autoconfigure.web.reactive.ReactiveWebServerFactoryAutoConfiguration
org.springframework.boot.autoconfigure.web.reactive.WebFluxAutoConfiguration
org.springframework.boot.autoconfigure.web.reactive.WebSessionIdResolverAutoConfiguration
org.springframework.boot.autoconfigure.web.reactive.error.ErrorWebFluxAutoConfiguration
org.springframework.boot.autoconfigure.web.reactive.function.client.ClientHttpConnectorAutoConfiguration
org.springframework.boot.autoconfigure.web.reactive.function.client.WebClientAutoConfiguration
org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration
org.springframework.boot.autoconfigure.web.servlet.HttpEncodingAutoConfiguration
org.springframework.boot.autoconfigure.web.servlet.MultipartAutoConfiguration
org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryAutoConfiguration
org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration
org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration
org.springframework.boot.autoconfigure.webservices.WebServicesAutoConfiguration
org.springframework.boot.autoconfigure.webservices.client.WebServiceTemplateAutoConfiguration
org.springframework.boot.autoconfigure.websocket.reactive.WebSocketReactiveAutoConfiguration
org.springframework.boot.autoconfigure.websocket.servlet.WebSocketMessagingAutoConfiguration
org.springframework.boot.autoconfigure.websocket.servlet.WebSocketServletAutoConfiguration

image-20251202173317496

C:\Users\Lenovo.m2\repository\org\springframework\boot\spring-boot-autoconfigure\3.5.7\spring-boot-autoconfigure-3.5.7.jar!\META-INF\spring\org.springframework.boot.autoconfigure.AutoConfiguration.imports

image-20251202173556375

@ConditionalOnMissingBean

image-20251202174045292

package com.example;

import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class HeaderConfig {

    @Bean
    @ConditionalOnClass(name = "io.jsonwebtoken.Jwts")//判断环境是否有对应的字节码文件，如果有就创建bean
    @ConditionalOnMissingBean//判断环境中没有这个bean才会创建bean
    @ConditionalOnProperty(name = "myname",havingValue = "itheima")//判断属性值是否等于（在yml文件里面）
    public HeaderParser headerParser(){
        return new HeaderParser();
    }

    @Bean
    public HeaderGenerator headerGenerator(){
        return new HeaderGenerator();
    }
}

@AutoConfiguration
@ConditionalOnClass({Gson.class})
@EnableConfigurationProperties({GsonProperties.class})
public class GsonAutoConfiguration {
    @Bean
    @ConditionalOnMissingBean
    public GsonBuilder gsonBuilder(List<GsonBuilderCustomizer> customizers) {
        GsonBuilder builder = new GsonBuilder();
        customizers.forEach((c) -> c.customize(builder));
        return builder;
    }

    @Bean
    @ConditionalOnMissingBean
    public Gson gson(GsonBuilder gsonBuilder) {
        return gsonBuilder.create();
    }

@ConditionalOnClass({Gson.class})就是有没有Gson的实现代码

image-20251202180339024

image-20251202180506393

自定义组件的starter

image-20251202180906513

只需要引入starter依赖（一个）

image-20251202181255008

在starter的pom里面

<dependency>
    <groupId>com.aliyun.oss</groupId>
    <artifactId>aliyun-oss-spring-boot-autoconfigure</artifactId>
    <version>0.0.1-SNAPSHOT</version>
</dependency>

image-20251202185038204

posted @ 2025-12-02 19:17  David大胃  阅读(10)  评论(0)    收藏  举报